U.S. patent application number 10/493334 was filed with the patent office on 2006-07-27 for pressure-sensitive sensor and monitor using the pressure-sensitive sensor.
Invention is credited to Kotaro Hayashi, Takanobu Makimura, Takanori Shibata.
Application Number | 20060162464 10/493334 |
Document ID | / |
Family ID | 19140072 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060162464 |
Kind Code |
A1 |
Hayashi; Kotaro ; et
al. |
July 27, 2006 |
Pressure-sensitive sensor and monitor using the pressure-sensitive
sensor
Abstract
A pressure-sensitive sensor (a pressure sensor) for measuring
the pressure applied to a pressure-receiving part by assuming the
pressure as an amount of deformation of the pressure-receiving part
and converting the amount of deformation into an electrical signal
and a monitor for monitoring the action and the state and change of
the emotional motion of a person through the pressure-sensitive
sensor, for example, a pet robot that senses the petting action of
the owner and performs a predetermined reaction and action are
disclosed. The sensor comprises at least two parallel electrode
sheets disposed in a spaced relationship from each other and an
expandable dielectric member interposed between the adjacent two
electrode sheets. When a pressure is exerted on the outermost
electrode sheet, the dielectric member deforms and its capacitance
varies.
Inventors: |
Hayashi; Kotaro; (Toyama,
JP) ; Makimura; Takanobu; (Toyama, JP) ;
Shibata; Takanori; (Iberaki, JP) |
Correspondence
Address: |
COOPER & DUNHAM, LLP
1185 AVENUE OF THE AMERICAS
NEW YORK
NY
10036
US
|
Family ID: |
19140072 |
Appl. No.: |
10/493334 |
Filed: |
May 29, 2002 |
PCT Filed: |
May 29, 2002 |
PCT NO: |
PCT/JP02/05227 |
371 Date: |
July 7, 2005 |
Current U.S.
Class: |
73/818 |
Current CPC
Class: |
A63H 2200/00 20130101;
G01L 9/0075 20130101; G01L 1/144 20130101; A61B 5/6896 20130101;
A61B 2562/02 20130101; A61B 5/16 20130101 |
Class at
Publication: |
073/818 |
International
Class: |
G01N 3/08 20060101
G01N003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 22, 2001 |
JP |
2001-323138 |
Claims
1. A pressure sensor device, comprising a pressure sensor including
at least two electrode sheets arranged in a spaced relationship
from each other at a predetermined distance and an expandable
dielectric member interposed between the two adjacent electrode
sheets, wherein its capacitance is allowed to vary due to
deformation of the dielectric member upon application of pressure
to the outermost electrode sheet; and a pressure detection means
connected to each of said electrode sheets for outputting a
pressure-sensitive signal in accordance with a variation in the
capacitance of said dielectric member by detecting the variation in
the capacitance thereof; wherein, as the variation in the
capacitance of said dielectric member, a variation in the
capacitance at a time interval between a current time point and a
time point preceding by a predetermined period of time from the
current time point.
2. The pressure sensor device as claimed in claim 1, wherein the
dielectric member is molded in a spongy form.
3. The pressure sensor device as claimed in claim 2, wherein a
liquid dielectric member is impregnated in the spongy dielectric
member.
4. The pressure sensor device as claimed in any one of claims 1 to
4, wherein each of said electrode sheets is flexible.
5. The pressure sensor device as claimed in any one of claims 1 to
4, wherein any of said electrode sheets is connected to a GND.
6. The pressure sensor device as claimed in any one of claims 1 to
5, wherein said pressure detection means comprises an oscillation
circuit arranged so as to depend the capacitance of the
pressure-sensitive sensor upon an oscillating cycle, a
charging-and-discharging circuit for repeating the charging and
discharging at every oscillating cycle of the oscillation circuit,
and a pressure detection circuit for detecting a magnitude of the
pressure applied to the pressure-sensitive sensor in a form of
comparison of a potential accumulated in a condenser of the
charging-and-discharging circuit with a predetermined threshold
value.
7. A pet robot comprising a main body having at least one action
part for conducting a predetermined action in response to an
instruction signal, a cover covering at least a portion of the main
body, a pressure-sensitive sensor as claimed in any one of claims 1
to 5, embedded in the main body and covered with the cover, wherein
the action part in electrically connected to a detection means and
is disposed to receive an output signal from the detection means as
an instruction signal.
8. A pressure-receiving structural member comprising a main body, a
cover covering at least a portion of the main body, and the
pressure sensor device embedded in the main body and covered with
the cover, as claimed in any one of claims 1 to 5.
9. The pressure-receiving structural member as claimed in claim 8,
wherein said main body is one member selected from the group
consisting of a stair chair, a walking chair, an automatic chair, a
bed, a coverlet, shoes and a keyboard.
Description
TECHNICAL FIELD
[0001] The present invention relates to a pressure-sensitive sensor
(a pressure censor) for converting an amount of deformation into an
electrical signal and detecting the amount of deformation by
treating a pressure applied to a pressure-receiving part as the
amount of deformation of the pressure-receiving part, to a monitor
for monitoring an action as well as the state and changes of an
emotional motion of a person through the pressure-sensitive sensor,
and to a pet robot for performing a predetermined reaction and
action by sensing the petting action of an owner.
BACKGROUND TECHNOLOGY
[0002] As pressure-sensitive sensors, there are known, among
others, those of the type that can detect an amount of the pressure
applied through a plurality of electrodes superposed on one other
with a spacing interposed therebetween within an elastic member by
allowing one or more of the facing electrodes to come into contact
with each other and transmitting electricity through the electrode
sheets by deforming the elastic member due to the application of
pressure, and those of the type for converting a pressure applied
to a pressure-receiving part into an electrical signal by using a
pressure-sensitive resistance member made from a pressure-sensitive
resistance member including, for example, a pressure-sensitive and
conductive rubbery material and so on and sense the electrical
signal.
[0003] As the former is of the type that can sense a contact or
non-contact between the facing electrodes, however, it cannot sense
a minute amount of pressure that causes no transforming the elastic
member. As the latter can be used in a limited field where a
pressure greater than a predetermined magnitude is applied, on the
other hand, because the pressure-sensitive and conductive rubbery
material has minute changes in output by the application of such a
minute pressure. Moreover, the pressure-sensitive sensors have the
structural problems that there is the tendency of the detecting
regions are dispersing in a discontinuous fashion within a narrow
scope and that non-sensitive points are dispersed even within a
region where the sensing of pressure is needed.
[0004] In addition, patent applications have already been filed,
for example, for inventions on the technology, in which a
pressure-sensitive sensor or switch is embedded inside a chair or a
bed, for sensing a state as to whether a person is seated or laid
on a chair or a bed, for sensing whether the person is a child or
an adult by setting a weight, or for changing a shape of the chair
or the bed in accordance with comfortableness. It can be
appreciated, however, that conventional inventions have been made
with the object to perceive the existence of a person, but they
have no object to assume the action of a person as well as a state
and a change of an emotional motion of the person.
DISCLOSURE OF THE INVENTION
[0005] The present invention has been completed with the above
background taken into account, and it has the object to provide a
pressure-sensitive sensor capable of sensing for sure a minute
pressure without forming any non-sensing band in a region where the
sensing of pressure is needed, to provide a monitor, for example,
with the pressure-sensitive sensor loaded therein, capable of
monitoring the action and the state of an emotional motion of a
person, and to provide, for example, a chair or a bed with the
monitor loaded therein, a pet robot, and a wearable interface.
[0006] The pressure-sensitive sensor according to the present
invention made for the purpose to solve the problems as described
above is characterized with a sensing part having electrode sheets,
including an electrode sheet working as a pressure-receiving face,
disposed in a spaced relationship from each other with an
expandable tangible dielectric member interposed therebetween. The
term "pressure-receiving face" as used herein is intended to mean a
face onto which the pressure is actually applied, whether directly
or indirectly. The term "expandable" and related terms as used
herein are each intended to mean a property of being deformable as
well as reproducible and include a concept of being so-called
elastic. The term "tangible" of the tangible dielectric member as
used herein is intended to mean a property of sustaining a certain
stable shape, excluding an unstable state, such as a liquid or
gel-like state.
[0007] The pressure-sensitive part is composed of a sandwich
structure with the electrode sheets and the tangible dielectric
member sandwiched therebetween so as to produce an action
equivalent of a condenser working as one of major electronic
circuit parts. The pressure-sensitive part may comprise a monolayer
structure, or a bilayer or polylayer structure, having a
pressure-sensitive part comprising three electrode sheets,
including the electrode sheet acting as the pressure-receiving
face, superposed on one other in a spaced relationship from each
other with the expandable tangible dielectric member interposed
therebetween.
[0008] The tangible dielectric member may be formed in a spongy
state so as to become likely to be deformed by the application of a
very minute amount of pressure. The tangible dielectric or may be
formed by immersion in a liquid dielectric member so as to heighten
a dielectric constant of the resulting tangible dielectric member.
Moreover, a flexible sheet may be used for the electrode sheet in
order to improve adaptability to the environment in which the
pressure-sensitive part is disposed. It is to be noted herein that
the flexible sheet may be appropriately chosen from sheets having a
property capable of being bent and/or twisted, and whether the
flexible sheet is provided with reproducibility can be determined
on the basis of the field of use. As specific examples of the
flexible sheet, there may be mentioned, for example, a flexible
substrate with an electrode material such as a copper foil or the
like attached to its front face, a conductive sheet with conductive
fibers intertwined like an electromagnetic shield material, or a
thin plate of a conductive metal.
[0009] The pressure-sensitive sensor according to the present
invention may be used for a pet robot having one of the above
illustrated pressure-sensitive sensors embedded under an outer
covering member as well as having a pressure detection means and a
reaction means inside the outer covering member, in which the
pressure detection means is designed so as to judge the presence
and absence of an electrical deformation generated by the
application of pressure to the pressure-sensitive part of the
pressure-sensitive sensor and to generate a pressure sensitive
signal upon judgment of the presence of the electrical signal
generated by the application of the pressure to the
pressure-sensitive part, and the reaction means is designed so as
to execute a predetermined motion in response to the
pressure-sensitive signal.
[0010] It is to be noted herein that the term "under the outer
covering member" is intended to mean a shallow portion at which the
pressure-sensitive sensor can function as a pressure-sensitive
sensor and it does not always physically mean to be immediately
under the outer covering member. As the outer covering member,
there may be mentioned, for example, a cloth, a sheet member or a
plate member, disposed to cover the outermost shell of an article,
such as a cover sheet, a protective sheet or a decorative sheet. In
the case where a stuffed toy is taken as am example, the outer
covering member corresponds to a knit, felt or woolen cloth, for
example, disposed as a skin. Further, the electrical deformation is
intended to include a deformation with regard to a predetermined
constant physical amount (an absolute deformation) or a periodical
deformation on the basis of a comparison of a physical amount
before a predetermined time with a current physical amount (a
relative deformation).
[0011] The pressure-sensitive sensor according to the present
invention may be used for a chair and a bed and as a wearable
interface.
Regarding a Chair:
[0012] The pressure-sensitive sensor can sense the presence of a
person on the basis of the manner of seating on the chair. It can
also measure a size of the person on the basis of the area on which
the pressure is exerted and estimate the weight of the person on
the basis of the pressure exerted per area. Such calibrations may
be carried out daily to recognize the persons who are seated and
monitor a variation of the weights of the persons and other
parameters.
[0013] (1) Regarding a Sheet of a Seat for Exclusive Use with a
Car:
[0014] In the case where a variation in a periodical low frequency
is detected by focusing attention on a variation in pressuree
exerted from tho back side of a person carrying out operations,
such as driving the car, a judgment is made such that the person
driving the car is most likely to fall into a doze.
[0015] (a) Input: A plane pressure-sensitive sensor is embedded
each in a seated face and a back face of the seat to detect the
pressure exerted thereon. Information from sensors other than the
seat sensors may be combined.
[0016] (b) Information processing: A state of the person sitting on
the seat is assumed by measuring the total sum of the pressure
exerted onto the sitting seat face or the back seat face or a
variation in the pressure per unit face with an elapse of time and
comparing the motion of the seated person with a human's motion
model by focusing on periodicity or the like.
[0017] (e) The control of other devices is carried out depending on
the assumed state of the driver so as to automatically let a
machine act onto the driver or assist the driver.
[0018] For example, when the car is driven at a low speed in
combination with car speed information, a fluctuation in the motion
of a person can be detected to judge as to whether the person
becomes nervous. If it is judged that the person is irritating,
then the car can act on the person so as to cool down in
association with a massaging function and/or a
configuration-changing function disposed in the seat and/or other
information media and so on.
[0019] (2) Regarding a Seat for an Airplane:
[0020] Monitoring is carried out as to whether a passenger's motion
changes in an appropriate fashion. If the passenger do not move for
a predetermined period of time, a signal can be given the passenger
to move, for example, in order to prevent an occurrence of problems
causing an economy syndrome or other problems that might be caused
to occur due to staying in an identical posture for a long
time.
Regarding an Office Chair:
[0021] (1) An office chair may be provided with a built-in plane
pressure-sensitive sensor in the sitting face and the back face of
the chair. This built-in plane pressure-sensitive sensor can
monitor the posture of the person in a state of sitting on the
chair or a variation in the posture thereof. Monitoring the posture
and the variation of the posture of the person can assist in
managing the working state and checking the working time of a
person sitting and working before a computer. Further, monitoring
the motion of the body of a working person can assist in the
management of an extent of fatigue or a health control of the
person. In addition, the chair can provide an active service by
positively moving the chair, massaging or other services, in the
case where a person is working while sitting on the chair
continuously during a long period of time.
[0022] (2) While a person is absent from the chair in office for a
long time, a telephone call to a fixed telephone can automatically
be transferred from the fixed telephone to another telephone
including a portable telephone or the like if the fixed telephone
would give no answer for a predetermined period of time. Further,
as the receiver is back to his office and seated on the chair, the
transfer is terminated within short and the telephone line is
switched and connected to the fixed telephone.
Regarding a Bed:
[0023] A pressure-sensitive sensor disposed in a bed can recognize
a person sleeping on the bed on the basis of a posture of the
sleeping person. The pressure-sensitive sensor measures a size of
the person on the basis of an area on which the pressure of the
person is exerted and presume the weight of the sleeping person on
the basis of a pressure per unit area exerted from the person
sleeping on the bed. This data is measured on a daily basis to
recognize the person and monitor a variation in the weight of the
person and other parameters.
[0024] (1) A plane pressure-sensitive sensor is embedded in a mat
of a bed to monitor the state in which person is sleeping. Further,
monitoring as to whether the person sleeping on the bed on a
periodical basis can prevent the death of an old person staying in
an old-age home or a baby sleeping with the face lied face
downward.
[0025] (2) A plane pressure-sensitive sensor is embedded in a
coverlet in order to recognize whether the coverlet is placed on
the sleeping person. The pressure-sensitive sensor can sense a
contact of the coverlet with the body of the sleeping person by
monitoring a variation in the pressure exerted on the coverlet. For
example, if the coverlet would fall from the bed side, this state
can be detected due to the fact that no pressure to be exerted on
the coverlet varies any longer.
Regarding a Key Board:
[0026] A plurality of plane pressure-sensitive sensors are used for
an input device for entering letters including, for example,
alphabets and kana letters. Letters can be chosen at a high speed
by changing the speed at which letters are changed due to changes
in pressure. A pressure-sensitive sensor can also be used as a
switch of a portable telephone for making an input of letters
variable.
Regarding an Electronic Wheelchair:
[0027] The pressure-sensitive sensor for use with an electronic
wheelchair can control the direction and the speed of moving the
wheelchair by moving the body of the person. A plane
pressure-sensitive sensor is embedded in the sitting face of the
seat of the electronic wheelchair. An instruction on the direction
of advancement of the wheelchair can be given to the wheelchair by
moving the gravity of the weight of the driver in all directions,
i.e., forwards, rearwards, leftwards and rightwards. The
pressure-sensitive sensor can be used as a replacement for an
existing joystick.
Regarding Shoes:
[0028] Checking the way of walking (in order to prevent the hallux
valgus): A plane pressure-sensitive sensor is embedded in inner
soles of shoes to monitor a portion of the sole of the foot on
which the body weight is exerted from the person wearing the shoes.
This allows checking a manner of standing or walking. While a
person in standing while working for a long time, a balance of the
body weight exerted on the left and right feet is monitored to give
the person working in a standing posture an instruction on the
necessity of resting or other information. Further, the
pressure-sensitive sensors disposed in the shoes can monitor the
time of walking and give the walker an advice for resting or
information on abnormality in the manner of walking as the weight
starts inclining towards the outside of the foot as time elapses.
These functions can prevent an occurrence of the hallux valgus and
check a manner of walking for an old person, thereby preventing a
crick in the back or the like.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0029] FIGS. 1(a) and 1(b) are schematic illustrations each showing
an example of a state of a variation due to stress of a pressure
application part in the pressure-sensitive sensor according to the
present invention.
[0030] FIG. 2 is a schematic illustration showing an example of a
state of connection of the pressure-sensitive sensor according to
the present invention to a pressure detection means.
[0031] FIG. 3 is a schematic illustration showing an example of a
pressure-sensitive sensor unit including the pressure-sensitive
sensor according to the present invention.
[0032] FIG. 4 is a schematic illustration showing an example of
disposition of the pressure-sensitive sensor according to the
present invention.
[0033] FIG. 5 is a circuit drawing showing an example of a pressure
detection means adopted for a pet robot using the
pressure-sensitive sensor according to the present invention.
[0034] FIGS. 6(a), (b) (c), (d), (e) and (f) are each a plan view
showing a cut example of the pressure-sensitive sensor according to
the present invention.
BEST MODES FOR CARRYING OUT THE PRESENT INVENTION
[0035] A description will now be given regarding the modes of
carrying out the pressure-sensitive sensor according to the present
invention as well as the modes of carrying out a pet robot using
the pressure-sensitive sensor, with reference to the accompanying
drawings.
[0036] The embodiment as shown in FIG. 4 is directed to a stuffed
toy 13 in the shape of a seal (hereinafter referred to as a
"robot"). The robot 13 is designed in such a manner that a
pressure-sensitive, sensor 7 (as shown in FIG. 6) is embedded each
at portions under an outer covering member 4, corresponding to the
trunk, tail, fin, head, flank, chest, buttocks and chin thereof, so
as to sense an electrical signal generated by the pressure applied
to the respective portions of the body of the toy 13. As shown in
FIG. 5, the robot is provided with a pressure detection means 5 and
a reaction means 6 inside the outer covering member, in which the
pressure detection means is designed so as to calibrate a physical
amount indicating an electrical deformation caused by a variation
in pressure applied by a pet stroke, hits or the like and sensed by
the pressure-sensitive sensors 7 and to generate a
pressure-sensitive signal in accordance with a magnitude of the
physical amount, and the reaction means is designed so as to
execute a predetermined motion in response to the
pressure-sensitive signal.
[0037] As shown in FIGS. 1 to 3, the pressure-sensitive sensor 7
comprises electrode sheets 1 and 1 disposed in a spaced
relationship, including an electrode sheet 1 acting as a
pressure-receiving face interposed between therebetween, and a
tangible dielectric member 2 made out of a urethane sponge having
an expandable property. The pressure-sensitive sensor also
comprises a pressure-sensitive part 3 composed of the electrode
sheets 1, 1, disposed in a spaced relationship with the electrode
sheet 1 acting as the pressure-receiving face interposed
therebetween and the expandable tangible dielectric member 2, and
each of the electrode sheets 1 is connected to a circuit of a
pressure detection means 5. The electrode sheet 1 is formed with a
thin plate from a raw material including, such as copper or the
like, and it in itself can play a role equivalent of a
counter-electrode of a condenser. As the electrode sheet 1, there
may be used, as needed, a flexible sheet made from a woven cloth or
an unwoven cloth, each made out of knitted wires or conductive
fibers so as to enable the pressure-sensitive sensor 7 to be
embedded under the outer covering member 4 of the robot in a curved
state.
[0038] In this embodiment, the tangible dielectric member 2 having
an expandable property is interposed among each of three electrode
sheets 1, 1 and 1, superposed in a spaced relationship from one
another. This structure can provide an electrical property
equivalent of that of two wide condensers connected in series to
each other through the central electrode sheet 1. It is to be
provided herein, however, that an electrically parallel connection
can be achieved in the case where an output is taken from the
second electrode 1 inside of the three electrodes 1, 1, 1, as shown
in FIGS. 2 and 5, and the outside two electrode sheets 1 and 1 are
connected to a GND of the pressure detection means 5. In this
embodiment, the urethane sponge may preferably comprise, for
example, a urethane sponge having density of approximately 20
kg/cm.sup.3 and hardness of approximately 19.6 N, while a feel upon
application of pressure or reproducibility after deformation is
taken into account. These parameters can be gained by impregnating
the tangible dielectric member 2 in a liquid dielectric member, as
needed. In such a case, however, it is needed to sufficiently seal
the pressure-sensitive sensor 7 with a sheathing material 14
composed of an insulating material having a low dielectric
constant.
[0039] As shown in FIG. 5, the pressure detection means 5 as used
in this embodiment comprises an oscillation circuit 8 designed to
act an oscillating cycle depending upon the capacitance of the
pressure-sensitive sensor 7, a charging-and-discharging circuit 9
designed so as to repeat the charging and the discharging at every
oscillating cycle of the oscillation circuit, and a pressure
detection circuit 10 designed so as to detect a magnitude of the
pressure applied against the pressure-sensitive sensor 7 in
comparison of the potential accumulated in a condenser C1 of the
charging-and-discharging circuit 9 with a predetermined threshold
value.
[0040] The charging-and-discharging circuit 9 is disposed in such a
manner that, in the case where the discharge is conducted at a
cycle of the oscillation circuit 8 at the time when no stress is
applied to the pressure-sensitive part 3 of the pressure-sensitive
sensor 7 (this instance being hereinafter referred to as
"stationary time"), a constant of CR is fixed to such an extent
that the lowest potential of the condenser of the
charging-and-discharging circuit 9 does not become lower than a
threshold value of the pressure detection circuit 10. On the other
hand, in the case where a stress is caused to occur due to the
pressure exerted on the pressure-sensitive sensor 7, the
oscillation circuit 8 causes a change (decrease) in the
electrostatic capacitance as the condenser of the
pressure-sensitive sensor 7 in accompany with the occurrence of the
stress, and a transmitting frequency of the oscillation circuit 8
is affected. In other words, a sample circuit as shown in FIG. 9
elongates a cycle in accordance with a magnitude of the pressure
applied upon the application of the stress to the
pressure-sensitive sensor 7, as compared with the cycle at the
stationary time.
[0041] As the oscillating cycle of the oscillation circuit 8
elongates, the discharging period of time becomes extended by the
elongation of the discharging time of the charging-and-discharging
circuit 9 and the lowest potential of the condenser becomes lower
than that at the stationary time as well as lower than the
threshold value of the pressure detection circuit 10. As a result,
a reverse output stage of the pressure detection circuit 10 outputs
a HI level only during the period of time when the threshold value
becomes lower, out of the period of time during which the
oscillating cycle becomes elongated. In this case, a change of a
duty ratio in the oscillating cycle is converted into a
predetermined potential via an integrating circuit 15 and outputted
as an analog non-stage pressure-sensitive signal in accordance with
the magnitude of the pressure applied. It is to be provided,
however, that, as the lowest potential of the condenser of the
charging-and-discharging circuit 9 does not become lower than the
threshold value of the pressure detection circuit 10 in a
stationary state, a LOW level is outputted as a pressure-sensitive
signal from the reverse output stage or the pressure detection
circuit.
[0042] The sample circuit is disposed in such a manner that a
stress produced in the pressure-sensitive sensor 7 is converted
into an electrophysical amount, that is a variation in the
capacitance due to the structure of the condenser of the
pressure-sensitive part 3, and finally the absolute amount as the
lowest potential of the condenser in the-charging-and-discharging
circuit 9 is compared with a threshold value that is an absolute
amount defined by the pressure detection circuit 10. This is
referred to as an "absolute amount comparison type". In some cases,
however, the pressure detection means 5 may adopt a pressure
detection circuit for comparing a variant portion of the electrical
deformation, such as a cycle, potential, pulse width, phase and so
on, corresponding to a stress to be produced in the
pressure-sensitive sensor at a periodical interval, under cases
taken into account where the shape of the pressure-sensitive part 3
of the pressure-sensitive sensor can not be recovered at the
stationary time due to stresses produced at very frequent occasions
and the capacitance cannot be returned to that at the stationary
time or where the pressure-sensitive sensor has already been forced
to be deformed at the time of embedding. This is referred to as a
relative amount comparison type".
[0043] As shown in FIG. 5, the sample circuit can judge versatile
states including, such as caressing, massaging, patting and so on,
and the presence or absence of stress by conducting a stepwise
judgment of an analog pressure-sensitive signal outputted from the
pressure detection circuit 10 in the potential thereof. Specific
techniques for adopting for the pressure detection circuit may be
appropriately selected from the existing techniques including, for
example, technique for detecting the potential by stages in the
manner as described above, technique for detecting the change in
the frequency caused by the addition of the stress in binary or
multiple stages, and technique for detecting the change in a phase
from the stationary state caused by the addition of the stress in
binary or multiple stages.
[0044] In the embodiment of the sample circuit as described above,
as measures for noises, an output is taken from the second
electrode sheet 1 interposed between the two outside electrode
sheets 1 and 1, as shown in FIGS. 2 and 5, and the two outside
electrode sheets 1 and 1 are connected to a GND of the pressure
detection means 5. It is provided, however, that a variety of
pressure detection means 5 may be disposed integrally with each of
the pressure-sensitive sensors 7, as shown in FIGS. 3 and 6, in
order to enable a sure detection of any minute variation in
capacitance in accordance with the structure and use of the
pressure-sensitive sensor 7 without interference from noises, and
it may be embedded as a pressure-sensitive sensor unit 11
connecting the pressure detection means 5 to the pressure-sensitive
sensors 7 through the shortest possible line.
[0045] The pressure-sensitive sensor unit 11 may be provided at
least with a pressure detection circuit for detecting the state of
the application of the pressure in the same manner as the pressure
detection circuit 10 by the various techniques as described above,
in the manner as shown in the sample circuit. In the case where the
judgment of a multi-stage level is needed, it may be provided with
a level judgment circuit (although not shown), much as an A/D
converted, for allocating the pressure detected by the pressure
detection circuit in stages to convert the output of the level
judgment circuit as a pressure-sensitive signal. Further, in the
case where it is considered appropriate to use, for the reaction
means 6, particularly an LED or the like, which is relatively small
in scale and simplified, a drive circuit 12 of the reaction means 6
including, for example, a current driver or a pulse generating
circuit, may be disposed. As the output of the level judgment
circuit which is allocated in stages, there may be used, for
example, an analog amount such as voltage or the like or a digital
value consisting of serial data or parallel data.
[0046] For instance, the pressure-sensitive signal from the
pressure detection circuit 10 in this embodiment may work as a
boosting signal for the drive circuit 12 for a corresponding
display-device or a corresponding actuator as the reaction means 6
to let the nose, the eyes, the front legs, or the rear legs of the
robot 13, for example, take an action in synchronism with the
predetermined reaction. It is provided, however, that the
pressure-sensitive sensor 7 can be used by cutting the
pressure-sensitive part into an appropriate shape so as to fit in
the embedding location, as shown in FIG. 6, and it can be used in
compliance with design needs by changing the design in a relatively
simple manner in accordance with the cut area even in the case
where the pressure detection circuit of the absolute amount
comparison type is adopted as well as in the case where the
pressure detection circuit of the relative amount comparison type
is adopted.
INDUSTRIAL UTILIZABILITY
[0047] As described above, the use of the pressure-sensitive sensor
according to the present invention can achieve the detection of the
status of the application of pressure at low costs and for sure
without using an expensive deformation gauge or pressure sensor and
in the absence of a non-sensitive band over the full area of the
pressure-sensitive part. Further, the pressure-sensitive parts of
versatile sizes can be manufactured in accordance with
specifications. Moreover, the structure of the pressure-sensitive
part, which is composed of the three electrode sheets, including
the electrode sheet acting as the pressure-receiving face, arranged
in a spaced relationship from one another with the expandable
tangible dielectric member interposed between the two outside
electrode sheets, enables measures of noises by using the two
sheets positioned outside as the GND. In addition, the molding of
the tangible dielectric member in a spongy form can relatively
easily change a design of a pressure band region to be detected and
the kind of the application of pressure (i.e., the spontaneous
application of pressure, the continuous application of pressure,
etc.) by adjusting a foaming density of the tangible dielectric
member. Moreover, the pressure-sensitive part can be loaded even in
a curved state by using a flexible sheet for the electrode
sheet.
[0048] Further, the pet robot using the pressure-sensitive sensor
according to the present invention can represent the reaction and
the action in a definite and sure way and at a quick timing by
surely detecting the state of the application of pressure to the
surface part by the pressure-sensitive sensors, thereby allowing an
attachment to the robot as compared with an actual living thing.
Moreover, the adoption of the periodically relative deformation by
using the state of the application of pressure as the electrical
deformation provides for convenience with respect to the
disposition and the control of the pressure-sensitive sensor,
thereby allowing the detection of the application of pressure over
every corner of the surface part of the pet robot. This fine
detection can realize an extremely fine reaction and action of the
pet robot in communication with a person as if the pet robot be an
actually living being.
* * * * *